What is formation in stratigraphy?
A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties. Formations are not defined on the thickness of the rock strata they consist of and the thickness of different formations can therefore vary widely.
What was the name of the Orogeny that formed what is now West Virginia?
The Appalachian Orogeny, a period of mountain building resulting from the collision of what is now North America with what is now Africa, peaked roughly 290 million years ago during the late Pennsylvanian. During that time, West Virginia was uplifted, sediment deposition ceased, and erosion began.
What Period of geologic time was most important to West Virginia?
Paleozoic Era By the Cambrian Period, approximately 541 to 485 million years ago, a shallow sea had spread westward over most of what is now West Virginia. Marine deposition took place throughout most of this and the succeeding Ordovician Period.
What is the geology of West Virginia?
Thick wedges of sandstone, shale and limestone piled up, all folded by later collisions to the east. Along West Virginia’s easternmost border, resistant, tilted sandstones form long ridges that parallel the fold axes, while less folded rock forms the horizontal layers of the Appalachian plateaus to the west.
What is Walther’s Law geology?
Walther’s Law states that any vertical progression of facies is the result of a succession of depositional environments that are laterally juxtaposed to each other.
What do you mean by formation?
1 : an act of giving form or shape to something or of taking form : development. 2 : something that is formed new word formations. 3 : the manner in which a thing is formed : structure the peculiar formation of the heart.
What caused most of the rock formations in WV?
Movements of the earth’s tectonic plates cause episodes of rifting and mountain building. Combined with subsequent erosion, production, and deposition of sediments these mountain-building episodes resulted in the geology of our state.
Was West Virginia ever under water?
West Virginia’s fossil record begins in the Cambrian. From that time through the rest of the early Paleozoic, the state was at least partially submerged under a shallow sea. The Paleozoic seas of West Virginia were home to creatures like corals, eurypterids, graptolites, nautiloids, and trilobites at varying times.
What has caused most of the rock formations in West Virginia?
Why is West Virginia so mountainous?
West Virginia is called the Mountain State because it’s the only state completely within the Appalachian Mountain region, and its average elevation is higher than any other state east of the Mississippi River!
What is Walther’s law used for?
Walther’s Law. This allows us to convert a vertical straigraphic section into a reconstructed map of original depositional environments, very powerful concept.